Problem about balun (hspice)

[twlin1]

This slide is from lecture note at UC Berkley.
There is error message on Xbalun2 when PSRR's simulating.
Isn't the balun bidirectional ?

The error message is showed below.
"no input to vccs/vcvs at node 0:vo_diff defined in subckt 0"

Can somebody help me to solve the problem ?
Thanks in advance !

You can see the spice file below.

*****************
***fully differential***
*****************
Xbalun1 vi 0 vp1 vn1 balun
R1 vp1 inn 1000meg
C1 vp1 inn 1p
C2 vn1 inp 1p
R2 vn1 inp 1000meg
C3 inn vss 10f
C4 inp vss 10f
R3 inn vp2 2000meg
C5 inn vp2 500f
C6 inp vn2 500f
R4 inp vn2 2000meg
*Xbalun2 vo_diff 0 vp2 vn2 balun
Gota1 vp2 vn2 poly(1) inp inn 1m


****************
***single-ended***
****************
Cs1 vi sen 1p
Rse1 vi sen 1000meg
Cx sen vss 10f
Rse2 sen vo_se 2000meg
Cs2 sen vo_se 500f
Gota2 vo_se 0 poly(1) 0 sen 1m

.subckt balun vdm vcm vp vm
e1 vp vcm transformer vdm 0 2
e2 vcm vm transformer vdm 0 2
.ends

vi vi 0 dc 0 ac 1
vss vss 0 -1.5
.ac dec 1000 100 100meg

.end

 

[Julian18]

yeah, I also want to know this.

Added after 5 minutes:

Isn't the balun bidirectional??

 

[xdy83]

is there a cap conected with vo_diff?

 

[Julian18]

I dont think so.

 

[yschuang]

I think you should add a big resistor at vo_diff